In a seemingly innocuous email Google have just announced a major change to the way that your budgets are handled within Google AdWords. In the old days you used to set a budget per day and then Google would cap itself at that. In addition, if you had underspent the previous day it would carry this (limited to a fixed percentage of your daily budget) forward to increase today’s budget, in an effort to smooth out peaks and troughs.
Google are in the process of changing this and will now (assuming you leave your budget fixed throughout the month) spent up to a monthly budget of the daily budget that you have set multiplied by 30.4 (average number of days per month).
This is actually a positive change for most people as campaigns are often underspent due to peaks and troughs not being evened out over a month (often requiring people to set higher budgets than they wanted to). It is – of course – also a positive change for Google who have at a stroke increased their potential AdWords revenue considerably!